Patent GB-397220-A (GB)
Title: Improvements in or relating to brake apparatus for railway vehicles
IPC: B60T13/66
Filed: 1932-03-14
Abstract: 397,220. Vacuum brakes. CONSOLIDATED BRAKE & ENGINEERING CO., Ltd., RAWLINGS, V. P., and PALMER, R. T., Windsor Works, Slough. March 14, 1932, No. 7566. [Class 103 (i).] In automatic vacuum brake apparatus for railway vehicles the brakes are applied by the admission of air to one side of the brake pistons either directly by electrically controlled valves or through the train-pipe by a valve operated mechanically by a handle mounted upon the driver's electric controller for the brakes, the degree of the electrically controlled application being dependent upon the current strength. Application of the brakes by the release of the usual " dead-man " pushbutton may be effected by energizing the electrically controlled valves or by a separate valve. The electrically controlled valves 7 each comprises chambers 33, 34, Fig. 3, connected respectively to the train-pipe 4 and to the lower chamber of the cylinder 5 and divided by a diaphragm 35 with which engages the plunger 45 of a solenoid. The stem of a valve 42 slides in a spider 44 and can engage the stem of a valve 36. The upper chamber of the cylinder 5 is exhausted by the train-pipe through the usual ball-valve or as shown the ball-valve 49 may be arranged in a separate connection 48 from the chamber 33, a spring-controlled valve 50 being provided for limiting the vacuum. The driver's brake controller 11 comprises fixed contacts 51, Fig. 5, for engagement with contacts 52 on the drum 55 rotatable by the handle 12. A spindle 58 also rotatable by the handle 12 and carrying a cam 59 can be depressed by a slidable tapered rod 65 by gripping the handle 56 so that rotation of the cam thus opens the valve 13 to admit air to the train-pipe. With the controller in the running position, the train wires 21, 22 are disconnected from the mains 25, 26 and the motor 2 of the exhauster. 1 is connected to the mains under the control of the exhauster governor switch 9 to maintain the vacuum in the train-pipe which is connected to the cylinders 5 through the valves 42, 49, Fig. 3. By turning the controller handle 12 current can be supplied to the trainwires and the solenoids of the valves 7 through resistances 23 that are gradually cut-out, thus causing the plungers 45 to raise the diaphragms 35, seating the valves 42 to cut off the trainpipe from the cylinders 5 and opening the valves 36 to admit air to the cylinders to apply the brakes. When the pressure in the cylinder and chamber 34 acting on the diaphragm 35 is sufficient to overcome the force exerted by the solenoid the diaphragm and valves move downwardly so that both valves are closed. Decreasing the current re-opens the valve 42 to exhaust the cylinder and release the brakes. When the controller is in the full release position the exhauster motor 2 is connected directly to the mains without the intervention of the governor 9. With the controller in any of its application positions, the valve 13 can be opened to apply the brakes by gripping the handle 56. The circuit from the mains to the controller includes contacts 53, 54, contact 54 being secured to the valve rod 58 so that electric application is cut-out when the valve 13 is opened. Admission of air to the train-pipe raises the diaphragm 35 to open the valve 36. In a modification of the valve, Fig. 3, the valve 42 is carried by the plunger 45 and seats on the underside of the diaphragm. Release of the safety or " dead-man " pushbutton applies the brakes by moving a switch 17 to the dottedline position in which it connects the trainwire 21 direct to the main, thus operating the valves 7 and/or it may de-energize a pilot valve 15, 16 controlling an emergency valve 14 to admit air to the train-pipe. To render the braking on each vehicle proportionate to the load thereon, a resistance may be provided for the solenoid of each valve 7 which can be set by a switch on the vehicles.